Cleaning Environment

Q.

Why are bacteria and fungi called decomposers? List any two advantages of decomposer to the environment.

Q.

How are nutrients recycled through ecosystems?

Q. An alga used in space travel is___

Q.

Aeration of water during wastewater treatment removes which of these?

1. Germs

2. Human waste

3. Bacteria

4. Insoluble things

Q.

Secondary sewage treatment in a sewage treatment plant is mainly a ______________ process.

1. biological

2. physical

3. mechanical

4. chemical

Q.

Which process of wastewater treatment is commonly known as sewage treatment?

Q.

Dumping sewage into rivers results to which of the following events?

1. Population decrease of microorganisms.

2. Population explosion of microorganisms.

3. Purification of the water body.

4. Increase in dissolved oxygen in the water body.

Q.

---

present in the roots of the pea plants can convert nitrogen gas present in the air into the form that plant can absorb

Q.

How can we stop algal bloom?

Q. Which of the following is mainly produced by the activity of anaerobic bacteria in sewage?

1. Marsh gas
2. Propane
3. Laughing gas
4. Mustard gas

Q.

Organisms that feed on the dead and decaying matter are ________.

Q. Which of the following is the first step in sewage treatment?

1. Sedimentation
2. Filtration
3. Flocculation
4. None of the above

Q.

How do microorganisms help in cleaning the environment?

Q. BOD or Biological Oxygen Demand is the level of oxygen needed in the water body for organisms to survive.

1. True
2. False

Q. Biogas is produced by the decomposition of the cow dung by the methanogens present in it.

1. True
2. False

Q. During sewage treatment, the microorganisms participate under which step?

1. Primary
2. Secondary
3. Tertiary
4. All of the above

Q.

The main constituent of biogas is:

1. butane

2. ethane

3. methane

4. alcohol

Q.

Aeration of water during wastewater treatment removes which of these?

1. Human waste

2. Bacteria

3. Germs

4. Insoluble things

Q. Biogas is produced by the decomposition of the cow dung by the methanogens present in it.

1. True
2. False

Q. A few lakes in a major metropolitan city start to become green in colour. Considering that there are numerous high raised apartments and housing complexes near these lakes, what could be the reason for the water turning green?

1. The sewage water from houses are flowing into the lake
2. The amount of organic nutrients has increased in the lake
3. The BOD of the lake has increased
4. Sudden boom in the growth of algae

Q. Once the floc acts on the nutrients in the effluent, the left over substance after sedimentation is called as ___ sludge.

Q. Which of the following is the first step in sewage treatment?

1. Sedimentation
2. Filtration
3. Flocculation
4. None of the above

Q.

Which of the following is true about biogas production?

1. The solid waste/cow dung used as raw material starts to ferment in the air tight chambers
2. Methanogens in the cow dung are the source of methane and hydrogen gas.
3. Anaerobic bacteria such as Methanobrevibacter and Methanomicrobium are responsible for the production of biogas
4. Biogas production leaves behind solid waste that is dumped into landfills.

Q. Consider the following assertion and reason, select the right option.
Assertion [A]: Mercury is one of the leading causes of pollution in oceans
Reasons [R]: Mercury turns into methylmercury, which is toxic.

1. Both A and R are correct and R explains A
2. Both A and R are correct and R does not explain A
3. A is correct and R is incorrect
4. Both A and R are incorrect

Q.

Organisms called methanogens are most abundant in:

1. Polluted stream

2. Hot spring

3. Sulphur rock

4. Cattleyard

Q. A few lakes in a major metropolitan city start to become green in colour. Considering that there are numerous high raised apartments and housing complexes near these lakes, what could be the reason for the water turning green?

1. The sewage water from houses are flowing into the lake
2. The amount of organic nutrients has increased in the lake
3. The BOD of the lake has increased
4. Sudden boom in the growth of algae

Q.

Secondary sewage treatment in a sewage treatment plant is mainly a ______________ process.

1. biological

2. physical

3. mechanical

4. chemical